Technology and innovation in mining: updating the MissionZero Mine

Low impact grinding

“A major development since 2021 is the acquisition of TK Mining in 2022,” England began. “The deal strengthens our position in HPGR, where we now lead the market with over 150 units installed. It also expands our IPCC installed base and offering, including the Rail-Running Conveyor™, which further lowers the carbon footprint of IPCC”.   

“We are now exploring HPGR for dry “finish” grinding,” continued England. “In addition, we are looking to apply the OK™ mill to mining. This vertical roller mill (VRM) technology is proven to deliver energy efficient grinding in the cement industry. A dry grinding VRM test facility has recently been commissioned in Salt Lake City with the first customer tests expected later this year.” 

Eco-beneficiation 

FLSmidth is scaling-up the coarseAIR™ coarse particle flotation cell technology, invented at Newcastle University by Professor Galvin. “Coarse flotation really is the heart of the MissionZero Mine, as it enables us to reduce grinding circuit energy, minimise raw water requirements, produce coarser tailings, and decrease the flotation circuit and solid liquid separation footprint,” explained England. “Importantly, the technology is expected to be applicable to many metal ores needed in the green transition.” 

The resulting coarse concentrate requires regrinding before further flotation to achieve required grades in the final concentrate. FLSmidth offers two technologies for modern regrind circuits: FTM a vertical agitated steel media mill, and the VXPmill, a vertical stirred ceramic media mill. “Both are proven to reduce energy and grinding media consumption when compared to horizontal ball mills for the same grinding duty, while also significantly reducing mill footprint and concrete foundation mass,” said England.

The largest FLS FTM (3356 kW) was installed and commissioned at a top-tier gold supplier in Dominican Republic, while in Canada, another gold supplier took delivery of the largest FLS VXPmill (3000 kW) in May 2023. 

A three year EIT RawMaterials-funded project – due to finish this year – is working to commercialise the REFLUX™ flotation cell (RFC). “RFC delivers fast and effective flotation, which raises the standard when it comes to concentrate grade and recovery, along with throughput capability” England said. The current EIT project has proven RFC significantly shifts the grade and recovery curve by up to 3-6%, while reducing energy consumption by 27% and increasing throughput up to 10 times. The first commercial RFC units are now available with the first unit contract signed in Q1 2024. There is significant interest in the fast flotation technology from customers in a range of commodities and geographies.

Water and tailings management  

Coarse flotation – with its coarser tailings – opens up opportunities for innovation in tailings disposal, such as EcoPaste, which focuses on improving safety and increasing process water recycling. “Coarse tailings are filtered using vacuum filtration and then mixed with finer, thickened paste tailings and waste rock/overburden to form geotechnically stable tailings,” explained England. “In laboratory testing, we have achieved coarse tailings with very low moisture. We have also added coarse particles to the fine tailings and seen dewatering rates dramatically improve.”  

For mines with lower strip ratios, “the use of filtered coarse tailings could reduce the amount of waste rock/overburden needed in the paste,” continued England. “Meanwhile, for mines adopting ore sorting, we can use reject material from that process in the EcoPaste. All these options are being considered in the MissionZero Mine and for mines that want to move away from wet impoundments.”  

FLSmidth has also developed an innovative thickener spiral rake blade, which was installed at a large copper mine in Kazakhstan, where it increased underflow densities by 11%, reduced tailings volume by 15%, and increased water recovery at the plant by 15%. Meanwhile, an improved automatic filter press (AFP) design offers the “highest filtration surface area and cake volume of any 2.5 m filter, reducing energy consumption, filter weight, footprint and wash water compared to the previous design,” said England. 

Digital and future MissionZero Mine flowsheets 

Digital solutions to support the MissionZero Mine are also being developed with FLSmidth investing in advanced process control (APC) systems, online condition monitoring and process optimisation services across the full flowsheet. “We have already seen some impressive results,” noted England. “In Chile, the implementation of an APC system on the tailings thickener resulted in 14% less water going to tailings, equating to 5.1 million m3/year of water, at an estimated cost of USD 18 million, that would otherwise have been lost to tailings.”   

Additional MissionZero Mine concepts are in the pipeline, and we have recently completed a desktop tradeoff and LCA study for a MissionZero lithium-spodumene concentration flowsheet that aims to significantly decarbonise the process. “We have been investigating the use of a stacked ABON® sizer system of Eccentric Roll Crusher (ERC) with VRM dry grinding to reduce the comminution energy consumption, as well as including the recovery benefits of RFC flotation technology to the lithium flowsheet,” said England.”

We have worked together with Minviro to understand the environmental impacts and costs of producing spodumene concentrate via the lithium MissionZero flowsheet, in comparison with conventional wet stack and dry stack lithium processes. The MissionZero flowsheet with vertical roller mill and dry stack tailings has a clear potential for reduced climate change and water use impacts.” England continues “We are also improving the spodumene conversion process, launching an indirect cooler with energy recovery, and developing complete pyromet island with preheater technology that has a much smaller carbon footprint, the first of which will be commissioned in Australia this year.”   

Flowsheets for other metals, low energy grinding circuits and tailing reprocessing plants are coming soon. These improvements will enhance sustainability, lower energy consumption, and reduced overall emissions. 

“We live in a world where words are no longer enough; we need action – and action now,” concluded England. “I am proud to be part of a company that is delivering on its promises and enabling a sustainable mining industry.”